Siblings Sora and Shiro, known collectively as "Blank," are reclusive gamers who dominate online competitions under their username. Despite their extraordinary skills, they struggle with social anxiety and isolation in the real world. One day, they receive a mysterious challenge from a being named Tet, who claims to be the God of Games. After winning the match, they are transported to Disboard, a world governed by the Ten Covenants, a set of rules that prohibit violence and require all conflicts to be resolved through games. In this world, races such as humans, elves, warbeasts, and others coexist, but humans are the weakest due to their lack of magical abilities.

Upon arrival, Sora and Shiro learn that Tet has tasked them with conquering all sixteen races and uniting the world under their rule. They begin their journey in Elkia, the last remaining human kingdom, which is on the brink of collapse due to poor leadership and constant losses in games against other races. The siblings quickly rise to prominence by defeating the kingdom's corrupt ruler in a game of chess, earning the trust of the people and the title of monarchs. With their strategic brilliance and unbreakable bond, they aim to challenge the other races and ascend to the position of the One True God, as Tet once did.

Throughout the series, Sora and Shiro face numerous challenges, including political intrigue, complex game mechanics, and the prejudices of other races. They form alliances with key characters, such as Stephanie Dola, the granddaughter of the former king, and Izuna, a warbeast envoy. Each game they play is a high-stakes battle of wits, often involving psychological manipulation, unconventional strategies, and clever exploitation of the rules. The siblings' ultimate goal is to create a world where no one loses, a utopia where games are the foundation of society.

The narrative explores themes of trust, cooperation, and the power of intellect over brute force. Sora and Shiro's dynamic is central to the story, with Sora's bold and charismatic personality complementing Shiro's calm and analytical demeanor. Their journey is marked by both triumphs and setbacks, as they navigate the complexities of Disboard's political landscape and confront their own insecurities. The series blends elements of fantasy, strategy, and humor, creating a unique and engaging story that appeals to fans of both gaming and adventure genres.